Automatic fluid supply and control means

ABSTRACT

For a system having a gas compressor and a compressed-gas receiver through-connected by a compressor-to-receiver discharge line and a receiver-to-compressor fluid supply line, and in which the receiver has a compressed-gas output line, an automaticallyoperative sub-system for controlling oil supply from the receiver to the compressor. The sub-system means include a flow-control valve signal-operative solely from fluid power, i.e., from receiver fluid pressure, to insure oil supply when the compressor starts up, and operative to insure oil supply cut-off when the compressor is halted.

United States Patent Holdsworth et al.

[451 Oct. 17,1972

[54] AUTOMATIC FLUID SUPPLY AND 211 Appl. No.: 114,479

[52] U.S. Cl. ..417/228 [51] Int. Cl. ..F04b 39/04, F04b 39/06 [58] Field of Search ..4l7/228 [56] References Cited I UNITED STATES PATENTS 3,349,994 10/1967 Bloom ..4l7/228 3,429,502 2/1969 Lundvik ..4l7/228 ATMOSPHERE Primary Examiner-Robert M. Walker Attorney-David W. Tibbott, Frank S. Troidl and Bernard J. Murphy [5 7 ABSTRACT For a system having a gas compressor and a compressed-gas receiver through-connected by a compressor-to-receiver discharge line and a receiver-to-compressor fluid supply line, and in which the receiver has a compressed-gas output line, an automatically-operative sub-system for controlling oil supply from the receiver to the compressor. The sub-system means include a flow-control valve signal-operative solely from fluid power, i.e., from receiver fluid pressure, to insure oil supply when the compressor starts up, and operative to insure oil supply cut-off when the compressor is halted.

11 Claims, 2'Drawing Figures PATENTEDnm 11 I972 Mn m mmm m .R mm

W J MHM .5 m MM 0a AUTOMATIC FLUID SUPPLY AND CONTROL MEANS This invention pertains to fluid supply and control means and in particular to such means automatically operative for cutting off the flow of fluid, suchas oil to an oil flooded air compressor, or like machine, when the machine is stopped, and operative to insure fluid supply to the machine at start-up.

Automatically-operative fluid supply and control means are known, of course, and typically they employ liquid flow control valves of either one of two types: the normally closed? or the normally open flow control valve. The normally closed valve has a disadvantage in thata signal, comprising a component of fluid pressure, or the like, is required to hold the valve open, and-if the signal should be interrupted, from whatever cause, the valve will close. This would result in a disastrous lack of supply of cooling oil for the gas compressor if, for instance, the means are deployed to such use. Thenormally open valve has a disadvantage in that, notoriously, and almost invariably, a spring is used to hold the valve open. Failure of the spring,-or a sticking of the valve, due to build up of gummy deposits, will result in there being insufficient force to open the valve, and again there would be a subsequent disastrous lack of supply of cooling oil, or like fluid, for the gas compressor or whatever.

It is an object of this invention to teach improved, automatically operative fluid supply and control means having none of the disadvantages, such as those just cited, which obtain in prior art supplyand control means.

Particularly, it is an object of this invention to set forth, for a system having a gas compressor and a compressed-gas receiver through-connected by a compressor-to-receiver discharge line and a receiver-to-compressor fluid supply line, and in which the receiver has a compressed-gas output line, automatically-operative fluid supply andcontrol means, comprising first fluidactuable valve means, having means for interruptive interpositioning thereof in said supply line, selectively operative in a plurality of positions for conducting a flow of fluid therethrough in a first operative position, and for interdicting a fluid flow therethrough in a second operative position, and control means coupled to said first valve means, having means for effecting a fluid through-connection thereof with said receiver and said compressor, automatically operative, in response to a start-up of said compressor, to dispose said first valve means in said first operative position solely by fluid power.

It is another object of this invention to teach automatically-operative fluid supply and control means, of the type just noted, inwhich the control means is further automatically operative, in response to the shut down of the compressor, to. dispose the first valve means in the second operative position solely by fluid power.

It is a feature of this invention to use a flow-control valve which is signal-operative soley from fluid power, i.e., from receiver fluid pressure, to admit oil therethrough for supply to the compressor, at compressor start-up, and to cut off the through supply of oil to the compressor, when the compressor is. halted, again, solely from fluid power.

'Further objects and features of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying figures in which:

FIG. 1 is a schematic diagram of a gas compressor and compressed-gas receiver system with which an embodiment of the novel fluid supply and control means has been operatively through-connected; and

FIG. 2 is an axial, cross-sectional view of the flowfcontrol valve of the FIG. 1 embodiment.

As shown in FIG. 1, a compressed-gas system 10 theredepicted comprises a gas compressor 12 and a compressed-gas receiver 14. A discharge line 16 conductsthe compressed-gas productto the receiver 14 from the compressor 12, by way of a check valve 18. The receiver 14 confines a reservoir of compressor cooling and sealing oil 20 which is supplied to the compressor 12 by a fluid supply line 22. Also, the receiver has a compressed-gas output line 24, and a compressed-gas device supply line 25. l

The fore-described compressed-gas system 10 is quite conventional for such'systems whichemploy an oil-flooded compressor, and it is proposed to represent compressor 12 herewith and herein as a compressor of that type.

The novel fluid supply and control means 26 here taught comprises a first, normally-open, flow-control valve 28 operatively and interruptively interpositioned in line 22, a second, normally-open, flow-control valve 30 similarly interpositioned in line24, first and second fluid-pressure pilot lines 32 and 34, respectively, and an orifice member 36, the latter restrictively interposed in line 24.

First flow-control valve 28, of our design, as FIG. 2 evidences, comprises a housing 38 which defines a chamber or cylinder 40 therewithin. A pair of spaced apart ports 42 and 44 open at either ends externally of the housing 38 and internally on cylinder 40. Port 42 is threaded to receive a first portion of line 22 thereat, for admittance of oil into the cylinder 40 from receiver 14, and port 44 is threaded to receive a second portion of line 22 thereat, for the conduct of oil from the cylinder 40 to the compressor 12. The oil 20 is admissible from port 42 toport 44, via a land 46 formed in housing 38, when the land is not obstructed. A piston 48 is movably disposed in the housing 38 for opening and for obstructing land 46.

Piston 48 is resiliently urged, by spring 50, normally to assume the position shown in full-line illustration in which land 46 is unobstructed. A third port 52 is formed in housing 38 and opens externally of the housing and internally onto a large bearing surface 54 of piston 48. Port 52 is threaded thereat to receive a termination of line 32. Fluidpressure admitted via port 52 bears upon surface 54, and the fluid pressure of the oil 20 admitted via port 42 is operative upon the small bearing surface 56 at the other end of piston 48.

A check valving element 58 is slidably mounted on a housing-carried rod 60 to close off port 42 in the absence of oil pressure thereat; in the full-line illustration of element 58 it is proposed to suggest that oil pressure causes a coursing of oil through ports 42 and 44. In the absence of oil pressure, element 58 assumes the dashed-line positioning shown; in the presence of fluid pressure at port 52, piston 48 assumes the dashedline positioning shown. Port 62 simply provides for a bleeding-off of oil or gas which leaks past the O-ring seals disposed about piston 48.

When the compressor 12 is operating normally, the valve 28 is in the open position, to conduct oil 20 from port 42 to port 44 the piston 48 being held by the spring 50, and by oil pressure on the small surface 56 of the piston. There is no pressure in the first pilot line 32 which is open to atmosphere through the connection of an end thereof with output line 24 and orifice member 36; valve 30 is closed at this time due to compressor operation. The receiver 14 is under compressor gas discharge pressure, accordingly, oil 20 flows from the receiver 14 through line 22, through the valve 28 and into the gas compressor 12. In the gas compressor 12, the oil is mixedwith the gas being compressed and is discharged back to the receiver 14 by way of the compressor discharge line 16.

When the compressor 12 is shut down the pressure in the gas compressor drops to atmospheric level, but the pressure in the receiver 14 is substantially above atmospheric pressure. Under these circumstances, the oil 20 in the receiver otherwise would flow through line 22 into the compressor 12 and out of the compressor air intake, if there were no oil shutoff valve.

To prevent this loss of oil, and flooding of the air intake cleaner elements, we have designed our automatic fluid supply and control means 26.

When the compressor 12 is shut down the pressure in the compressor discharge line 16 falls to atmospheric levels upstream of check valve 18. This causes the pressure in pilot line 34 to fall to atmospheric pressure. This allows the normally-open, second flow-control valve 30 to open and exhaust the pressure from the receiver 14 to atmosphere through the restrictive orifice member 36. The orifice member 36 has a restrictive orifice so sized, in relation to the valve 30 that at all significant receiver pressures it will maintain a marked pressure differential thereacross. Accordingly, the pressure in pilot line 32 will be substantially equal to the pressure in the receiver 14.

The pressure in pilot line 32 acts on the large surface 54 of the piston 48. The area of the large surface 54 of the piston 48 is configured to be at least 1% times greater than the area of the small surface 56 of the piston 48. The pressure in pilot line 32 acting on the large surface 54 of the piston 48 thus overcomes both spring 50 and the oil pressure in line 22 acting on the small surface 56 of the piston 48, and the valve 28 closes, preventing the flow of oil into the compressor 12 with the consequences described before.

When all pressure has been vented from the receiver 14, the pressure in pilot line 32 will drop to atmospheric, and the spring 50 should return the piston 48 of valve 28 to the open position ready for the next time the compressor 12 is started. Should the spring 50 become fractured or loose its resilience or should the piston 48 become stuck due to gummy deposits in the oil 20, oil pressure, from subsequent compressor startup, acting on the small surface 56 of the piston 48 will create sufficient force to cause the piston to move to the open position.

Our novel fluid supply and control means 26 accomplishes the following functions: l Automatically shuts off the oil flow to the compressor 12 solely on a fluidpower signal which only occurs when the compressor is shut down. (2 The valve 28 normally re-opens immediately afterv all pressure is relieved from the receiver 14. (3) In the event of spring failure normally to open the valve 28, or the build-up of gummy deposits on piston 48, the system oil pressure alone will force open the valve 28, allowing for normal flow, with subsequent start-up of the compressor 12.

While we have described our invention in connection with a specific embodiment thereof, it is to be clearly understood that this is done only by way of example and not as a limitation to the scope of our invention as set forth on the objects thereof and in the appended claims.

We claim: 1. For a system having a gas compressor and a compressed-gas receiver through-connected by a compressor-to-receiver discharge line and a receiver-to-compressor fluid supply line, and in which the receiver has a compressed gas output line, automatically operative fluid supply and control means, comprising:

first fluid actuable valve means, having means for interruptive interpositioning thereof in said supply line, selectively operative in a plurality of positions for conducting a flow of fluid therethrough in a first operative position, and for interdicting a fluid flow therethrough in a second operative position; and control means coupled to said first valve means, having means for effecting a fluid through-connection thereof with said receiver and said compressor, automatically operative, in response to a start-up of said compressor, to dispose said first valve means in said first operative position solely by fluid power; wherein said control means is further automatically operative in response to shut down of said compressor, to dispose said first valve means in said second operative position solely by fluid power; and

said fluid through-connection effecting means, of said control means, comprises a first fluid-pressure pilot line having opposite ends thereof coupled to and opening on said valve means and said output line, for accomodating a conduct of actuating fluid from said output line to said first valve means to effect a disposal of the latter in said second operative position, and a second fluid-pressure pilot line having one end thereof coupled to and opening on said discharge line; and further including second fluid actuable valve means, having means for interruptive interpositioning thereof in said output line, selectively operative in a plurality of positions for conducting a flow of fluid therethrough in a given operative position, and for interdictin g a fluid flow therethrough in another operative position; and

wherein the other end of said second fluid-pressure means for operative interpositioning in said output line to effect a maintenance of said actuating fluid, in said first fluid-pressure pilot line, at a pressure substantially equal to that of pressure of gas in said receiver. 3. Fluid supply and control means, according to claim 2, wherein:

said pressure-maintenance means comprises an orifice member, said member having a restrictive orifice defined therewithin for impeding fluid flow therethrough and to effect a control of de-pressurization of gas in said receiver. 4. Fluid supply and control means, according to claim 3, wherein:

said orifice member has oppositely disposed admittance and discharge ports, and said admittance port is disposed for direct fluid flow communication thereof with said first fluid pressure pilot line. 5. Fluid supply and control means, according to claim 1, wherein:

said second fluid actuable valve means, in the absence of an address thereto of actuating fluid via said second pilot line, is normally disposed in said given operative position. 6. Fluid supply and control means, according to claim 1, wherein:

said first fluid actuable valve means, in the absence of an address thereto of actuating fluid via said first pilot line, is normally disposed in said first operative position. 7. Fluid supply and control means, according to claim 6, wherein:

said first fluid actuable valve means comprises a housing having a cylinder defined therewithin, and first and second spaced-apart ports formed in said housing, each of said first and second ports opening on said cylinder and externally of said housing, and wall means movably disposed within said cylinder both for interrupting and for permitting fluid communication between said first and second ports, said first and second ports each having means for threadedly coupling a portion of said supply line thereto; and

wherein said wall means is movably responsive to 5 pressure of fluid in said supply line, to provide fluid communication between said ports and to accomodate a conduct of fluid through said housing.

8. a fluid supply and control means, according to claim 7, wherein:

said wall means comprises a piston and means engaging surfaces of both said piston and said housing for urging said piston to a disposition which facilitates a fluid communication between said first and second ports.

9. Fluid supply and control means, according to claim 8, further including:

a third port formed in said housing, spaced from said first and second ports, and opening on said cylinder and externally of said housing, said third port having means for threadedly coupling one end of said first fluid-pressure pilot line thereto; and

wherein said piston is movable responsive to pressure of fluid in said first fluid pressure pilot line to interrupt fluid communication between said first and second ports and to interdict a conduct of fluid through said housing. l0. Fluid supply and control means, according to claim 9, wherein:

said piston defines fluid pressure bearing surfaces at opposite ends thereof, one of said surfaces being disposed for address of fluid thereto only by way of said first fluid pressure pilot line, and the other of said surfaces being disposed for the address of fluid thereto only by way of said supply line, and said surfaces having different area dimensions. 11. Fluid supply and control means, according to claim 10, wherein:

said one surface comprises an area greater than that of said other surface. 

1. For a system having a gas compressor and a compressed-gas receiver through-connected by a compressor-to-receiver discharge line and a receiver-to-compressor fluid supply line, and in which the reCeiver has a compressed gas output line, automatically operative fluid supply and control means, comprising: first fluid actuable valve means, having means for interruptive interpositioning thereof in said supply line, selectively operative in a plurality of positions for conducting a flow of fluid therethrough in a first operative position, and for interdicting a fluid flow therethrough in a second operative position; and control means coupled to said first valve means, having means for effecting a fluid through-connection thereof with said receiver and said compressor, automatically operative, in response to a start-up of said compressor, to dispose said first valve means in said first operative position solely by fluid power; wherein said control means is further automatically operative in response to shut down of said compressor, to dispose said first valve means in said second operative position solely by fluid power; and said fluid through-connection effecting means, of said control means, comprises a first fluid-pressure pilot line having opposite ends thereof coupled to and opening on said valve means and said output line, for accomodating a conduct of actuating fluid from said output line to said first valve means to effect a disposal of the latter in said second operative position, and a second fluid-pressure pilot line having one end thereof coupled to and opening on said discharge line; and further including second fluid actuable valve means, having means for interruptive interpositioning thereof in said output line, selectively operative in a plurality of positions for conducting a flow of fluid therethrough in a given operative position, and for interdicting a fluid flow therethrough in another operative position; and wherein the other end of said second fluid-pressure pilot line is coupled to and opens on said second valve means, said second fluid pressure pilot line accomodating a conduct of actuating fluid from said discharge line to said second valve means to effect a disposal of said second valve means in said another operative position.
 2. Fluid supply and control means, according to claim 1, further including: means for operative interpositioning in said output line to effect a maintenance of said actuating fluid, in said first fluid-pressure pilot line, at a pressure substantially equal to that of pressure of gas in said receiver.
 3. Fluid supply and control means, according to claim 2, wherein: said pressure-maintenance means comprises an orifice member, said member having a restrictive orifice defined therewithin for impeding fluid flow therethrough and to effect a control of de-pressurization of gas in said receiver.
 4. Fluid supply and control means, according to claim 3, wherein: said orifice member has oppositely disposed admittance and discharge ports, and said admittance port is disposed for direct fluid flow communication thereof with said first fluid pressure pilot line.
 5. Fluid supply and control means, according to claim 1, wherein: said second fluid actuable valve means, in the absence of an address thereto of actuating fluid via said second pilot line, is normally disposed in said given operative position.
 6. Fluid supply and control means, according to claim 1, wherein: said first fluid actuable valve means, in the absence of an address thereto of actuating fluid via said first pilot line, is normally disposed in said first operative position.
 7. Fluid supply and control means, according to claim 6, wherein: said first fluid actuable valve means comprises a housing having a cylinder defined therewithin, and first and second spaced-apart ports formed in said housing, each of said first and second ports opening on said cylinder and externally of said housing, and wall means movably disposed within said cylinder both for interrupting and for permitting fluid communication between said first and second ports, said first and second ports each having means for threadedly Pg,12 coupling a portion of said supply line thereto; and wherein said wall means is movably responsive to pressure of fluid in said supply line, to provide fluid communication between said ports and to accomodate a conduct of fluid through said housing.
 8. A fluid supply and control means, according to claim 7, wherein: said wall means comprises a piston and means engaging surfaces of both said piston and said housing for urging said piston to a disposition which facilitates a fluid communication between said first and second ports.
 9. Fluid supply and control means, according to claim 8, further including: a third port formed in said housing, spaced from said first and second ports, and opening on said cylinder and externally of said housing, said third port having means for threadedly coupling one end of said first fluid-pressure pilot line thereto; and wherein said piston is movable responsive to pressure of fluid in said first fluid pressure pilot line to interrupt fluid communication between said first and second ports and to interdict a conduct of fluid through said housing.
 10. Fluid supply and control means, according to claim 9, wherein: said piston defines fluid pressure bearing surfaces at opposite ends thereof, one of said surfaces being disposed for address of fluid thereto only by way of said first fluid pressure pilot line, and the other of said surfaces being disposed for the address of fluid thereto only by way of said supply line, and said surfaces having different area dimensions.
 11. Fluid supply and control means, according to claim 10, wherein: said one surface comprises an area greater than that of said other surface. 